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Domestic species, including equids, were introduced in the Galapagos Islands in the XIX century. Equine vector-borne diseases are circulating in South America but their occurrence in the Galapagos Island was unknown. The objective of this study was to detect the occurrence of West Nile virus (WNV), Usutu virus (USUV) and equine infectious anemia virus (EIAV) in the four Galapagos Islands raising equids if they were present at a prevalence >1%. Serum samples were collected from 411 equids belonging to 124 owners from April to July 2019. All the results were negative to the ELISA tests used suggesting that WNV, USUV and EIAV are not circulating in the equine population of the Galapagos Islands.
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In Paraguay, whose main economic activity is cattle raising, bovine brucellosis is an endemic disease. Between May 2019 and October 2020, a national prevalence survey was implemented by the Paraguayan Veterinary Services. In the frame of that survey, a cross-sectional study was conducted in the eastern region of Paraguay to identify the risk factors that could be associated with brucellosis-positive farms and to estimate the bovine brucellosis seroprevalence and farmers' awareness about the disease. A questionnaire was administered to farmers to collect data on potential risk factors for bovine brucellosis as well as awareness on the disease. A logistic regression model was used to identify the risk factors associated with a farm brucellosis positive status. Blood samples were collected from 2551 cattle on 133 farms. The overall apparent seroprevalence was 27.8 % (95 % CI: 20.4-36.3 %) at the farm level, and 5.5 % (95 % CI: 4.7-6.5 %) at the animal level. Among 18 potential risk factors, four were associated with a farm brucellosis positive status. Farm size was associated with a higher risk of positive status in medium (20-80 cows) and large farms (>80 cows), compared with small farms (<20 cows). Barn disinfection had a protective effect on the risk of positive status. Conversely, presence of dogs and not incinerating/burying aborted material increased this risk. Even if 89 % of the farmers acknowledged being aware of the bovine brucellosis transmission to humans, only 46% of these farmers declared using protective gloves during calving or when handling abortions. The findings of this study emphasize the importance of implementing biosecurity measures and proper disposal of aborted material to control the disease. Therefore, to control the disease in Paraguay, vaccination campaigns should be accompanied by awareness campaigns addressing good farm management practices to minimize the risk of introduction and maintenance of brucellosis as well as the risk of human infection.
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Galápagos Penguin (Spheniscus mendiculus), Flightless Cormorant (Phalacrocorax harrisi), and Waved Albatross (Phoebastria irrorata) are among the most vulnerable species to natural and anthropogenic factors in the Galápagos Islands. In 2017, a dedicated study was conducted to detect Chlamydiaceae on cloacal swabs collected from 59 albatrosses, 68 penguins, and 10 cormorants in different islands and sites in the Galápagos Archipelago. A real-time PCR method targeting the conserved 23S ribosomal RNA gene of the Chlamydiaceae family detected the presence of the bacterium only in albatrosses from Punta Suárez, Española Island, with 21 positive samples (35.6%), whereas negative results were obtained with available real-time PCR systems specific to Chlamydia psittaci and Chlamydia abortus. Multilocus sequence typing (MLST) of the most strongly positive samples revealed a new sequence type closely related to the recently described avian strains of C. abortus. For a quick identification, a new real-time PCR system that allows the detection of all strains (avian and ruminant) belonging to the C. abortus species has been developed. Applied to a second set of samples from 31 albatrosses collected at Punta Suárez, Española Island, in 2018, the new real-time PCR system confirmed the presence of this bacteria in this group of birds, with the same new MLST sequence type.
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Chlamydia , Chlamydiaceae , Spheniscidae , Animais , Tipagem de Sequências Multilocus/veterinária , Chlamydia/genética , Chlamydiaceae/genética , RuminantesRESUMO
Beef exports represent a substantial part of Paraguay's agricultural sector. Cattle movements involve a high risk due to the possible spread of bovine diseases that can have a significant impact on the country's economy. We analyzed cattle movements from 2014 to 2018 using the networks analysis methodology at the holding and district levels at different temporal scales. We built two types of networks to identify network characteristics that may contribute to the spread of two diseases with different epidemiological characteristics: i) a network including all cattle movements to consider the transmission of a disease of rapid spread like foot and mouth disease, and ii) a network including only cow movements to account for bovine brucellosis, a disease of slow spread that occurs mainly in adult females. Network indicators did not vary substantially among the cattle and cow only networks. The holdings/districts included in the largest strongly connected components were distributed throughout the country. Percolation analysis performed at the holding level showed that a large number of holdings should be removed to make the largest strongly connected component disappear. Higher values of the centrality indicators were found for markets than for farms, indicating that they may play an important role in the spread of an infectious disease. At the holding level (but not at the district level), the networks exhibited characteristics of small-world networks. This property may facilitate the spread of foot and mouth disease in case of re-emergence, or of bovine brucellosis in the country through cattle movements. They should be taken into account when implementing surveillance or control measures for these diseases.
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Brucelose Bovina , Doenças dos Bovinos , Doenças Transmissíveis , Febre Aftosa , Feminino , Bovinos , Animais , Febre Aftosa/epidemiologia , Paraguai , Meios de Transporte , Doenças dos Bovinos/epidemiologiaRESUMO
Foot-and-mouth disease (FMD) is one of the most contagious viral animal diseases. It is an old disease which still poses a permanent threat of re-emergence for free zones. Foot-and-Mouth Disease Virus (FMDV), a Picornavirus belonging to genus Aphthovirus affects domestic and wild artiodactyls. FMD has a considerable socio-economic impact on agricultural production and trade in endemic regions, but also when incursions occur into FMD free areas, as in Europe in 2001. FMDV is historically one of the most studied viruses. Due to its high genetic and antigenic variability, the absence of cross-immunity between its seven serotypes, its ability to survive in the environment, its high contagiousness, its wide range of hosts and its particular biology, FMDV remains of major interest in animal health and the subject of many research projects. This review presents different aspects of FMDV infection, ranging from basic biology to diagnosis, surveillance and control.
La fièvre aphteuse (FA) est l'une des maladies virales animales les plus contagieuses. Bien que très ancienne, la FA reste toujours d'actualité et représente une menace permanente de réémergence pour les pays indemnes. Le virus de la FA ou FMDV (pour foot-and-mouth disease virus), de la famille Picornaviridae, genre Aphthovirus, affecte les artiodactyles domestiques comme sauvages (principalement bovins, ovins, caprins, porcins, camélidés et cervidés). La fièvre aphteuse a un impact socio-économique considérable sur la production et le commerce agricoles en zone d'enzootie mais également en cas d'incursion dans une zone précédemment indemne comme ce fut le cas en 2001 en Europe. Le virus de la FA est historiquement l'un des virus les plus étudiés. Par sa grande variabilité génétique et antigénique, l'absence d'immunité croisée entre ses sept sérotypes, sa capacité de survie dans l'environnement, sa grande contagiosité, son large spectre d'hôtes ainsi que sa biologie particulière, ce virus reste d'intérêt majeur en santé animale et l'objet de nombreux travaux de recherche. Cette revue vise à présenter différents aspects de l'infection par le virus de la fièvre aphteuse et ses problématiques actuelles, de la biologie fondamentale au diagnostic en passant par la surveillance et les moyens de lutte.
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Artiodáctilos , Vírus da Febre Aftosa , Febre Aftosa , Animais , Vírus da Febre Aftosa/genética , Febre Aftosa/diagnóstico , Febre Aftosa/epidemiologia , Febre Aftosa/prevenção & controle , Sorogrupo , Europa (Continente)/epidemiologiaRESUMO
We used cattle movement data in Ecuador for 2017 and 2018 to build two types of cattle networks: a network including all cattle movements accounting for a disease of rapid spread like foot and mouth disease and a network including only the cows accounting for brucellosis, a disease of slow evolution occurring mainly in adult females. Parishes (the smallest geographical units) were considered as nodes and cattle movements between parishes as links. Network indicators calculated at the annual and monthly levels were close for both types of networks. For both networks, the largest strong component at the annual level included > 90% of nodes and the largest weak component included all nodes indicating a very low fragmentation. A percolation analysis indicated that most of the parishes needed to be removed to eliminate the largest strong components. Based on some network characteristics we established that a highly transmissible disease could spread rapidly and that an infection of slower transmission such as brucellosis could spread within local clusters. These features should be taken into account when considering preventing measures in Ecuador in the case of an emerging disease like foot and mouth disease or control measures for an endemic disease like brucellosis.
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Brucelose , Doenças dos Bovinos , Febre Aftosa , Animais , Brucelose/veterinária , Bovinos , Doenças dos Bovinos/prevenção & controle , Equador/epidemiologia , Feminino , Febre Aftosa/epidemiologia , Meios de TransporteRESUMO
Mexico is one of the world's major poultry producing countries. Two significant challenges currently facing the poultry industry are the responsible and judicious use of antimicrobials, and the potential occurrence of infectious disease outbreaks. For example, repeated outbreaks of highly pathogenic avian influenza virus subtype H7N3 have occurred in poultry since its first detection in Mexico in 2012. Both of these challenges can be addressed through good husbandry practices and the application of on-farm biosecurity measures. The aims of this study were: (i) to assess the biosecurity measures practiced across different types of poultry farms in Mexico, and (ii) to collect information regarding antimicrobial usage. A cross-sectional study was carried out through on-farm interviews on 43 poultry farms. A multiple correspondence analysis was performed to characterize the farms based on their pattern of biosecurity practices and antimicrobial usage. Three clusters of farms were identified using an agglomerative hierarchical cluster analysis. In each cluster, a specific farm type was predominant. The biosecurity measures that significantly differentiated the visited farms, thus allowing their clusterization, were: the use of personal protective equipment (e.g. face masks, hair caps, and eye protection), the requirement for a hygiene protocol before and after entering the farm, the use of exclusive working clothes by staff and visitors, footbath presence at the barn entrance, and the mortality disposal strategy. The more stringent the biosecurity measures on farms within a cluster, the fewer the farms that used antimicrobials. Farms with more biosecurity breaches used antimicrobials considered critically important for public health. These findings could be helpful to understand how to guide strategies to reinforce compliance with biosecurity practices identified as critical according to the farm type. We conclude by providing certain recommendations to improve on-farm biosecurity measures.
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Antibacterianos/uso terapêutico , Influenza Aviária/prevenção & controle , Doenças das Aves Domésticas/prevenção & controle , Aves Domésticas , Criação de Animais Domésticos , Animais , Galinhas/virologia , Surtos de Doenças/veterinária , Fazendas , Humanos , Vírus da Influenza A Subtipo H7N3/efeitos dos fármacos , Vírus da Influenza A Subtipo H7N3/patogenicidade , Influenza Aviária/virologia , México/epidemiologia , Doenças das Aves Domésticas/virologiaRESUMO
Chlamydiaceae infections in poultry are mainly due to Chlamydia psittaci and Chlamydia gallinacea. While C. psittaci has long been known to affect birds and to have zoonotic potential, C. gallinacea is a newly described species that has been found to be widespread in chickens. As no data were available regarding the presence of Chlamydiaceae in Mexican poultry, a cross-sectional survey to detect the presence of Chlamydiaceae on commercial and backyard farms was carried out in eight federal states of Mexico with a high poultry density. Individual cloacal swabs were collected on 14 large-scale commercial poultry farms with controlled environment houses, 23 large-scale commercial poultry farms with open-sided houses, and 16 backyard farms. Samples were tested using a specific Chlamydiaceae real-time PCR technique. Chlamydial species were subsequently identified by a species-specific real-time PCR method. Information on potential risk factors was collected through a questionnaire. Logistic regression was performed to identify risk factors associated with Chlamydiaceae-positive results at the farm level on commercial farms. For backyard farms, a mixed-effect logistic regression model was used to consider information collected either at the animal or at the farm level. Overall, 7.1 % (n = 1/14) of controlled environment commercial farms, 26.1 % (n = 6/23) of open-sided commercial farms, and 75.0 % (n = 12/16) of backyard farms were Chlamydiaceae-positive. Apparent prevalence increased inversely to the level of confinement (controlled environment vs open-sided poultry houses vs backyards). Chlamydia gallinacea was the only chlamydial species detected. On commercial farms, egg-laying hen flocks had 6.7 times higher odds of being Chlamydiaceae-infected than broilers flocks (OR = 6.7, 95 % CI: 1.1-44.3, p = 0.04). On backyard farms, two variables were significantly associated with Chlamydiaceae infection: the lack of antibiotic use (OR = 8.4, 95 % CI: 1.84-38.49, p = 0.006), and an impaired health status (OR=8.8, 95 % CI: 1.9-38.9, p = 0.004). Further studies should be carried out to investigate the impact of C. gallinacea infection on egg quality and production performance in egg-laying hen flocks.
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Criação de Animais Domésticos/métodos , Galinhas , Infecções por Chlamydiaceae/veterinária , Chlamydiaceae/isolamento & purificação , Perus , Animais , Infecções por Chlamydiaceae/epidemiologia , Infecções por Chlamydiaceae/microbiologia , Coturnix , Estudos Transversais , Patos , Fazendas , Galliformes , México/epidemiologia , Prevalência , Fatores de RiscoRESUMO
Bluetongue virus serotype 8 (BTV-8) caused an epizootic in Europe in 2006/09. Transplacental transmission of BTV-8 was demonstrated leading to abortions, congenital malformations or nervous clinical signs in newborn calves. BTV-8 re-emerged in France in 2015. Although the re-emergent strain is nearly genetically identical to the one that had circulated in 2006/2009, it has caused very few clinical cases. However, from mid-December 2018 to April 2019, cases of calves with congenital malformations or displaying nervous clinical signs occurred in some departments (French administrative unit) in mainland France. Blood samples from these animals were sent to local laboratories, and the positive ones were confirmed at the French Bluetongue reference laboratory (BT-NRL). Out of 580 samples found positive at the local laboratories, 544 were confirmed as RT-PCR BTV-8 positive. The 36 samples found positive in the local laboratories and negative in the BT-NRL were all at the limit of RT-PCR detection. Hundred eighty-eight of the confirmed samples were also tested for the presence of Schmallenberg virus (SBV) and bovine virus diarrhoea virus (BVDV) infection: 4 were found positive for BVDV and none for SBV. The main clinical signs recorded for 244 calves, for which a reporting form was completed by veterinarians, included nervous clinical signs (81%), amaurosis (72%) and decrease/ no suckling reflex (40%). Hydranencephaly and microphthalmia were reported in 19 calves out of 27 in which a necropsy was practiced after death or euthanasia. These results indicate that the re-emergent strain of BTV-8 can cross the transplacental barrier and cause congenital malformations or nervous clinical signs in calves.
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Vírus Bluetongue/isolamento & purificação , Bluetongue/epidemiologia , Doenças dos Bovinos/virologia , Transmissão Vertical de Doenças Infecciosas/veterinária , Animais , Bluetongue/congênito , Bluetongue/virologia , Bovinos , Doenças dos Bovinos/epidemiologia , Feminino , França/epidemiologia , Gravidez , Estações do Ano , SorogrupoRESUMO
In the last 10 years, many atypical novel members of Brucella species have been reported, including several Brucella inopinata-like strains in wild-caught and "exotic" amphibians from various continents. In 2017, a strain of Brucella was isolated for the first time in animals from a French farm producing frogs-Pelophylax ridibundus-for human consumption and identified as B. microti-like. Following this first isolation, investigations were performed in this farm as well as in the farm of the research unit that provided the domestic frog strain to estimate the prevalence of B. microti-like infection and its presence in the surrounding environment. Farming practices were investigated and samples including frogs at different development stages, surface tank swabs, water, feed and soil were analysed by real-time PCR and bacteriological methods. High B. microti-like prevalence values (higher than 90%) were obtained in frog samples in the commercial farm, and its presence was highlighted in the environmental samples except feed. In the research unit farm, B. microti-like species was also isolated and detected in frog and environmental samples. These results show that B. microti-like organisms are able to colonize amphibians and persist in their environment. Its presence could constitute a possible risk for consumers and workers proving the importance of assessing the zoonotic and pathogenic potentials of these new and atypical Brucella species.
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Brucella/isolamento & purificação , Brucelose/veterinária , Ranidae/microbiologia , Animais , Cruzamento , Brucella/genética , Brucelose/epidemiologia , Brucelose/microbiologia , Meio Ambiente , Fazendas , França/epidemiologia , Humanos , Prevalência , ZoonosesRESUMO
Bluetongue virus (BTV) is a Culicoides-borne pathogen infecting both domestic and wild ruminants. In Europe, the Red Deer (Cervus elaphus) (RD) is considered a potential BTV reservoir, but persistent sylvatic cycle has not yet been demonstrated. In this paper, we explored the dynamics of BTV1 and BTV8 serotypes in the RD in France, and the potential role of that species in the re-emergence of BTV8 in livestock by 2015 (i.e., 5 years after the former last domestic cases). We performed 8 years of longitudinal monitoring (2008-2015) among 15 RD populations and 3065 individuals. We compared Culicoides communities and feeding habits within domestic and wild animal environments (51,380 samples). Culicoides diversity (>30 species) varied between them, but bridge-species able to feed on both wild and domestic hosts were abundant in both situations. Despite the presence of competent vectors in natural environments, BTV1 and BTV8 strains never spread in RD along the green corridors out of the domestic outbreak range. Decreasing antibody trends with no PCR results two years after the last domestic outbreak suggests that seropositive young RD were not recently infected but carried maternal antibodies. We conclude that RD did not play a role in spreading or maintaining BTV in France.
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Animais Selvagens/virologia , Vírus Bluetongue/fisiologia , Ceratopogonidae/virologia , Cervos/virologia , Reservatórios de Doenças/virologia , Animais , Animais Domésticos/virologia , Anticorpos Neutralizantes , Anticorpos Antivirais , Bluetongue/epidemiologia , Bluetongue/transmissão , Bluetongue/virologia , Vírus Bluetongue/imunologia , Ceratopogonidae/classificação , Surtos de Doenças , Feminino , França/epidemiologia , Gado/virologia , Masculino , Ruminantes/virologia , Doenças Transmitidas por Vetores/virologiaRESUMO
Bluetongue virus serotype 8 (BTV-8) was reported for the first time in Europe in 2006, causing the largest bluetongue outbreak ever recorded. France was mostly impacted in 2007/09. Trade restrictions were implemented all along. Vaccination became available from 2008: a limited number of doses was first administered in an emergency vaccination campaign, followed by two nationwide compulsory vaccination campaigns in 2009 and 2010. France regained a disease-free status in December 2012, but BTV may have kept circulating undetected as infected herds have been reported again since August 2015. We developed a stochastic dynamic compartmental model of BTV transmission in cattle and sheep to analyze the relative importance of vector active flight and host movements in disease spread, and assess the effectiveness of control measures. We represented BTV transmission both within and between French administrative subdivisions called cantons, during the 2007/09 outbreak and until the end of 2010, when compulsory vaccination was interrupted. Within-canton transmission was vector-borne, and between canton transmission could occur through three contact networks that accounted for movements of: (i) vectors between pastures located at close distance; (ii) cattle and sheep between pastures of the same farm; (iii) traded cattle. We estimated the model parameters by approximate Bayesian computation, using data from the 2007 French outbreak. With this framework, we were able to reproduce the BTV-8 epizootic wave. Host movements between distant pastures of the same farm were found to have a major contribution to BTV spread to disease-free areas, thus raising practical questions about herd management during outbreaks. We found that cattle trade restrictions had been well complied with; without them, the whole French territory would have been infected by winter 2007. The 2008 emergency vaccination campaign had little impact on disease spread as almost half vaccine doses had likely been administered to already immune cattle. Alternatively, establishing a vaccination buffer zone would have allowed a better control of BTV in 2008: limiting its spatial expansion and decreasing the number of infected cattle and sheep. We also showed a major role of compulsory vaccination in controlling the outbreak in 2009 and 2010, though we predicted a possible low-level circulation after the last detection.
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Bluetongue/epidemiologia , Bluetongue/transmissão , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Surtos de Doenças/veterinária , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/transmissão , Animais , Teorema de Bayes , Bovinos , França/epidemiologia , Modelos Teóricos , Prevalência , Estudos Soroepidemiológicos , OvinosRESUMO
Bluetongue is a vector-borne disease of ruminants with economic consequences for the livestock industry. Bluetongue virus serotype 8 (BTV-8) caused a massive outbreak in Europe in 2006/2009 and re-emerged in France in 2015. Given the unprecedented epidemiological features of this serotype in cattle, the importance of secondary routes of transmission was reconsidered and transplacental transmission of BTV-8 was demonstrated in naturally and experimentally infected cattle. Here we used surveillance data from the on-going outbreak to quantify BTV-8 vertical transmission in French cattle. We used RT-PCR pre-export tests collected from June to December 2016 on the French territory and developed a catalytic model to disentangle vertical and vector-borne transmission. A series of in silico experiments validated the ability of our framework to quantify vertical transmission provided sufficient prevalence levels. By applying our model to an area selected accordingly, we estimated a probability of vertical transmission of 56% (55.8%, 95% credible interval 41.7-70.6) in unvaccinated heifers infected late in gestation. The influence of this high probability of vertical transmission on BTV-8 spread and persistence should be further investigated.
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Bluetongue/transmissão , Transmissão Vertical de Doenças Infecciosas/veterinária , Animais , Bluetongue/epidemiologia , Vírus Bluetongue/fisiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Surtos de Doenças/veterinária , Feminino , França/epidemiologia , Transmissão Vertical de Doenças Infecciosas/estatística & dados numéricos , Prevalência , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Estações do AnoRESUMO
Bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV) have both been reported in mainland Ecuador, but their occurrence was unknown in the Galapagos Islands, an Ecuadorian province. We aimed to detect BTV or EHDV in cattle from the 3 main cattle-producing Galapagos Islands at a between-herd design prevalence of 20% and a within-herd design prevalence of 15%. Blood samples were collected from 410 cattle in 33 farms and tested for antibodies against BTV and EHDV by competitive ELISAs. All results were negative, suggesting that BTV and EHDV are not present in the Galapagos Islands.
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Vírus Bluetongue/isolamento & purificação , Bluetongue/epidemiologia , Doenças dos Bovinos/epidemiologia , Vírus da Doença Hemorrágica Epizoótica/isolamento & purificação , Infecções por Reoviridae/veterinária , Animais , Anticorpos Antivirais/sangue , Bluetongue/diagnóstico , Bluetongue/virologia , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/virologia , Equador/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Prevalência , Infecções por Reoviridae/diagnóstico , Infecções por Reoviridae/epidemiologia , Infecções por Reoviridae/virologiaRESUMO
The growing frequency of bluetongue virus (BTV) incursions in Europe in recent years led to the largest BTV outbreak ever recorded in 2006/09, with a dramatic impact on the cattle and sheep industries. The complex epidemiology of this vector-borne disease of ruminants and its recent emergence need to be better understood to identify and implement efficient control strategies. Mathematical models provide useful tools for that purpose; many of them have been developed in the light of the 2006/09 outbreak. We aimed to provide a systematic review of compartmental mathematical models dedicated to BTV occurrence or transmission in European countries, to assess robustness of findings to different modelling approaches and assumptions. We identified relevant papers from PubMed and Scopus databases, 21 of which were included in the review following the selection process laid out in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. We systematically extracted data from these papers to address the diversity and evolution of modelling approaches, and to identify important characteristics for future model development. Then, we summarized the main insights provided into bluetongue epidemiology, and discussed the relevance of these models as tools for risk mapping and for the design of surveillance and control systems. On the whole, the mechanistic models reviewed provided flexible frameworks, yielding mostly epidemiological insights specific to geographical areas and study periods. Despite the limitations of these models that sometimes relied on strong assumptions, we advocate their use to facilitate and inform evidence-based decision-making in animal health.
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Bluetongue/prevenção & controle , Bluetongue/transmissão , Modelos Teóricos , Animais , Vírus Bluetongue , Bovinos , Europa (Continente) , Ruminantes , OvinosRESUMO
Foot-and-mouth disease (FMD) is of major concern in most countries including Europe, where no outbreaks have occurred since a decade. Indeed, the risk of FMD introduction from infected countries is not negligible and the awareness of field stakeholders (farmers, veterinarians) is essential to ensure an effective detection of the viral circulation. The French veterinary services launched in 2015 a survey to estimate the awareness of farmers and veterinarians and their knowledge about epidemiological and regulatory aspects of FMD. Official health visits were used to collect information from cattle farmers and veterinarians through two separate questionnaires. The results show that not all cattle farmers were aware of the risk of FMD reintroduction in France and of its routes of infection and speed of dissemination. As for the veterinarians, their promptness to report a suspicion was dependent on the occurrence of FMD cases in European countries. These results highlight key aspectsregarding FMD epidemiology which should be regularly reminded to the field stakeholders in FMD-free countries to increase their awareness and thus ensure an effective early detection in case of FMD introduction.
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Fazendeiros/psicologia , Febre Aftosa , Conhecimentos, Atitudes e Prática em Saúde , Médicos Veterinários/psicologia , Animais , Febre Aftosa/epidemiologia , Febre Aftosa/prevenção & controle , França , HumanosRESUMO
Bluetongue virus is a vector-borne pathogen affecting ruminants that has caused major epidemics in France. Reconstructing the history of bluetongue in French cattle under control strategies such as vaccination has been hampered by the high level of sub-clinical infection, incomplete case data and poor understanding of vaccine uptake over time and space. To tackle these challenges, we used three age-structured serological surveys carried out in cattle (Nâ¯=â¯22,342) from ten administrative subdivisions called departments. We fitted catalytic models within a Bayesian MCMC framework to reconstruct the force of seroconversion from infection or vaccination, and the population-level susceptibility per semester between 2007 and 2016. In the departments of the study area, we estimated that 36% of cattle had been infected prior to vaccine rollout that became compulsory from July 2008. The last outbreak case was notified in December 2009, at which time 83% of the animals were seropositive, under the cumulative effect of vaccination and infection. The probability of seroconversion per semester dropped below 10% after 2010 when vaccination became optional. Vaccine uptake was smaller during the 2012 campaign than during the one in 2011, with strong regional contrasts. Eighty four percent of cattle were susceptible when bluetongue re-emerged in 2015. Thus, serological surveys can be used to estimate vaccine uptake and the magnitude of infection, the relative effect of which can sometimes be inferred using prior knowledge on reported incidence and vaccination dates.
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Bluetongue/epidemiologia , Bluetongue/transmissão , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/transmissão , Bovinos , Epidemias , Animais , Teorema de Bayes , Bluetongue/prevenção & controle , Vírus Bluetongue , Doenças dos Bovinos/prevenção & controle , França/epidemiologia , Programas de Imunização , VacinaçãoRESUMO
To define the bottlenecks that restrict antigen expression after oral administration of viral-vectored vaccines, we tracked vectors derived from the human adenovirus type 5 at whole body, tissue, and cellular scales throughout the digestive tract in a murine model of oral delivery. After intragastric administration of vectors encoding firefly luciferase or a model antigen, detectable levels of transgene-encoded protein or mRNA were confined to the intestine, and restricted to delimited anatomical zones. Expression of luciferase in the form of multiple small bioluminescent foci in the distal ileum, cecum, and proximal colon suggested multiple crossing points. Many foci were unassociated with visible Peyer's patches, implying that transduced cells lay in proximity to villous rather than follicle-associated epithelium, as supported by detection of transgene-encoded antigen in villous epithelial cells. Transgene-encoded mRNA but not protein was readily detected in Peyer's patches, suggesting that post-transcriptional regulation of viral gene expression might limit expression of transgene-encoded antigen in this tissue. To characterize the pathways by which the vector crossed the intestinal epithelium and encountered sentinel cells, a fluorescent-labeled vector was administered to mice by the intragastric route or inoculated into ligated intestinal loops comprising a Peyer's patch. The vector adhered selectively to microfold cells in the follicle-associated epithelium, and, after translocation to the subepithelial dome region, was captured by phagocytes that expressed CD11c and lysozyme. In conclusion, although a large number of crossing events took place throughout the intestine within and without Peyer's patches, multiple firewalls prevented systemic dissemination of vector and suppressed production of transgene-encoded protein in Peyer's patches.
Assuntos
Adenovírus Humanos/genética , Adenovírus Humanos/imunologia , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Transgenes/genética , Transgenes/imunologia , Administração Oral , Animais , Feminino , Expressão Gênica , Genes Reporter , Vetores Genéticos/administração & dosagem , Humanos , Imunização , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Camundongos , Especificidade de Órgãos , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Fagócitos/metabolismo , Transporte Proteico , VacinaçãoAssuntos
Doenças dos Animais/epidemiologia , Infecções por Bunyaviridae/veterinária , Surtos de Doenças/veterinária , Vigilância de Evento Sentinela/veterinária , Doenças dos Animais/virologia , Animais , Infecções por Bunyaviridae/epidemiologia , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/virologia , França/epidemiologia , Doenças das Cabras/epidemiologia , Doenças das Cabras/virologia , Cabras , Ovinos , Doenças dos Ovinos/epidemiologia , Doenças dos Ovinos/virologia , Análise Espaço-TemporalRESUMO
BACKGROUND: Anaplasma phagocytophilum is the causative agent of tick-borne fever, a disease with high economic impact for domestic ruminants in Europe. Epidemiological cycles of this species are complex, and involve different ecotypes circulating in various host species. To date, these epidemiological cycles are poorly understood, especially in Europe, as European reservoir hosts (i.e. vertebrate hosts enabling long-term maintenance of the bacterium in the ecosystem), of the bacterium have not yet been clearly identified. In this study, our objective was to explore the presence, the prevalence, and the genetic diversity of A. phagocytophilum in wild animals, in order to better understand their implications as reservoir hosts of this pathogen. METHODS: The spleens of 101 wild animals were collected from central France and tested for the presence of A. phagocytophilum DNA by msp2 qPCR. Positive samples were then typed by multi-locus variable-number tandem repeat (VNTR) analysis (MLVA), and compared to 179 previously typed A. phagocytophilum samples. RESULTS: Anaplasma phagocytophilum DNA was detected in 82/101 (81.2%) animals including 48/49 red deer (98%), 20/21 roe deer (95.2%), 13/29 wild boars (44.8%), and 1/1 red fox. MLVA enabled the discrimination of two A. phagocytophilum groups: group A contained the majority of A. phagocytophilum from red deer and two thirds of those from cattle, while group B included a human strain and variants from diverse animal species, i.e. sheep, dogs, a horse, the majority of variants from roe deer, and the remaining variants from cattle and red deer. CONCLUSIONS: Our results suggest that red deer and roe deer are promising A. phagocytophilum reservoir host candidates. Moreover, we also showed that A. phagocytophilum potentially circulates in at least two epidemiological cycles in French cattle. The first cycle may involve red deer as reservoir hosts and cattle as accidental hosts for Group A strains, whereas the second cycle could involve roe deer as reservoir hosts and at least domestic ruminants, dogs, horses, and humans as accidental hosts for Group B strains.